1. Field of the Invention
The present invention relates generally to coaxial cable connectors and, more particularly, but not by way of limitation, to push-on, pull-off coupling mechanisms for coaxial cable connectors.
2. History of Related Art
A coaxial cable is generally characterized by having an inner conductor, an outer conductor, and an insulator between the inner and outer conductors. The inner conductor may be hollow or solid. At the end of coaxial cable, a connector is attached forming a coaxial cable assembly and facilitating mechanical and electrical coupling of the coaxial cable to electronic equipment and other cables. The method of and apparatus for the mechanical and electrical coupling of the connector to the coaxial cable has for a number of years been the subject of considerable design innovation. For example, to effectuate electrical contact between the inner contact of the connector and the inner conductor of the cable, the inner contact may be soldered or otherwise secured in some other fashion to the inner conductor. To effectuate electrical contact between the body member of the connector and the outer conductor of the cable, a myriad of design issues arise. One design issue relates to the configuration of the outer conductor of the cable. A connector for a coaxial cable having an outer conductor and a hollow, plain cylindrical inner conductor is, for example, described in U.S. Pat. No. 3,199,061 (Johnson et al.). The Johnson patent describes a self-tapping connector. Such connectors are time-consuming to install and relatively expensive to manufacture. Also, when the inner connector is made of brass, over-tightening causes the threads to strip off the connector rather than the end portion of the inner conductor of the cable, and thus the connector must be replaced. More recent coaxial connector designs have addressed methods of and apparatus for quickly and easily attaching a connector to a coaxial cable with improved efficiency. U.S. Pat. No. 5,802,710, assigned to the assignee of the present invention, and incorporated herein by reference, teaches a method of attaching a connector to a coaxial cable that allows the depth of the inner contact relative to the body member of the connector to be easily controlled. In this manner, the depth of the inner contact relative to the body member of the connector is consistent from one assembly to the next. The method set forth therein also provides a moisture barrier between the cable and the connector without the use of rubber O-rings, thereby protecting the connector from detrimental environmental conditions.
Another very important design aspect of coaxial connectors has been, and currently is, the coupling mechanism that facilitates an interlocking engagement between mating male and female coupling sections. For example, U.S. Pat. No. 4,941,846 (Guimond, et al.) describes a quick connect/disconnect connector for coaxial cables which can be used with unmodified standard coaxial couplings having externally facing threads. The connector includes a connector housing having a plurality of movable fingers which have inwardly facing ridge portions that mesh with the externally facing threads of the coaxial coupling. When the connector coaxial line segment is pushed onto the coupling, the fingers move in such a way as to allow the ridge portions to interlock with the screw threads. The connector can be used for RF microwave such as SMA, TNC, Type N, etc. Disconnecting is accomplished by pulling the sleeve backward which releases the fingers from their interlocking position.
Another connector design addressing the coupling mechanism is set forth and shown in U.S. Pat. No. 4,138,181 (Hacker, et al.). The Hacker patent describes a releasable electrical connector having a receptacle component and a plug component which can be mated by relative rotation between the components and separated by a straight breakaway force. Pins on the receptacle components are engaged in a spring biased sleeve in the plug component. Moreover, a spring is provided around the male coaxial connector and biases the connector body toward the receptacle to provide better contact between the connectors.
Likewise, U.S. Pat. No. 4,545,633 (McGeary) generally describes a male plug and a female receptacle that are connected together by means of fingers on the male plug which are spread and are held by the female receptacle. The connector is unplugged by sliding a sleeve rearwardly against an internal spring and moving the locking tabs to an unlocked position.
Similarly, U.S. Pat. No. 6,267,612B1 (Arcykiewicz, et al.) teaches an adaptive coupling mechanism incorporating a multi-lined locking ring to engage the threads of a conventional rotational coupling system member.
These and related designs exemplify the innovation in the effort for improved high performance coaxial cable connector couplings that are easy and fast to install and uninstall one to the other under field conditions and which may also be economically manufactured.
It has been well established that connectors incorporating push-pull coupling assemblies permit faster installation than the threaded coupling assemblies. Typical push-pull couplings also often provide more reliable locking mechanisms because vibrations will have a less tendency to cause disconnection as compared to threaded connectors which are more prone to the deleterious effect of vibration. There are obviously no xe2x80x9ccross-threadingxe2x80x9d problems with push-pull connectors, because such problems are by definition the problem of threaded engagement. Also, push-pull connectors are quicker to connect or disconnect. However, threaded coupling assemblies, when installed correctly, are more physically secure (they do not disconnect when something pulls on them) whereas push-pull connectors, by definition, disconnect when a sufficient axial force is applied. However, to connect the typical push-pull connectors, the connector must be pulled in a rearward direction with respect to the female end to allow the connector to xe2x80x9copen upxe2x80x9d. Stated another way, the only way to xe2x80x9copen upxe2x80x9d the connector to allow receipt of a female end is to move the connector in a rearward direction; the connector cannot xe2x80x9copen upxe2x80x9d by moving the connector towards the female end. Then the connector may be pushed onto the female end and the connector is moved back to its default position to lock the connector in place. This may be cumbersome in the field because the user must pull the connector back while pushing the entire assembly into engagement with the female end.
It would be a distinct advantage to provide a push-on, pull-off connector that quickly connects with a standard threaded female coaxial end, without having to screw the connector on to the female end, that provides efficient and reliable coupling of the male and female connector members under field conditions. Also, it would be advantageous if the connector could allow receipt of the female end by either pushing or pulling the connector with respect to the female end. Enhanced coupling aspects, such as increased axial compression between male and female connection members, provide improved reliability. The present invention provides such a reliable coaxial connector coupling with a reciprocally mounted sleeve positionable around a connector member in three separate positions for enhanced ease of coupling/decoupling to a female end. The push-pull connector described herein includes a pair of springs for urging the female connector into engagement with the male coaxial connector while providing both locked and unlocked positions therebetween.